The U.S. Department of Energy (DOE) has published the final evaluation report from a GATEWAY demonstration on Franklin D. Roosevelt Drive, a heavily traveled New York City freeway with elevated portions. Four different types of LED roadway luminaires—each from a different manufacturer—were purchased in 2009 and compared with the incumbent high-pressure sodium (HPS) luminaries. Some of the key findings include,
- Significant energy savings were achieved with the LED products. All of the LED luminaires had lower energy usage than the incumbent baseline HPS luminaire, using 26 to 57 percent less energy.
- Three of the LED luminaires matched the initial illuminance of the HPS luminaire, but only two would meet the required maintained (i.e., long-term) illuminance values identified in RP-8-00 (without considering dirt depreciation).
- The LED systems all offered better color rendering and emitted no uplight compared to the HPS system. The improved color rendering resulting from the broader spectrum of the LEDs may bring with it better identification and contrast for improved visual acuity.
- The cost-effectiveness of the LED products in this application depends on the high electricity rates and deferred costly maintenance, as well as on the manufacturers’ claimed lifetimes.
The full report can be downloaded from the US DOE website.